Measurement-while-drilling (MWD) and Logging-while-drilling (LWD) systems are examples of surveying and well-logging procedures that may be used to provide information on the conditions at the drill bit, properties of the geologic formations being drilled, etc. This information may be stored for later retrieval, or transmitted via telemetry uphole to the operator at the surface, and used to guide and optimize the drilling process. Rotary Steering Tools (RST) are commonly used to steer well trajectories and require control signals and/or data to be transmitted from surface to the down hole tool.
Various forms of telemetry may be used in drilling and well-logging to transmit control and data signals downhole, and transmit the information collected by the downhole sensors uphole, including mud-pulse telemetry, hard wire connections, acoustic telemetry systems, electromagnetic (EM) telemetry, and the like. These sensors may be disposed predominantly at the downhole end of the drillstring. In a shallower or shorter well, the data may be conveyed without requiring signal boost or amplification.
In a deeper or longer well, it may be necessary to extend the range of the transmitter apparatus used to get information to or from the surface. In order to maintain an adequate signal-to-noise ratio to preserve signal quality along the transmission path, devices to boost signal strength, or repeaters, may be required.
A problem may arise in a system having repeaters or similar units for re transmission of signals when one of the units ceases to function within normal parameters. The unit may fail outright or may scramble the signal upon retransmission, sending only useless signals. With a weak or broken link in the transmission chain, the drilling operators may be effectively blind, with no way to determine where the problem is, what the problem is, whether it is an equipment failure or a temporary signal disruption due to geologic or other seismic conditions surrounding the drill string or the like.
In order to minimize the disruption in the well-drilling process, systems and methods that enable development of alternate data transmission routes in a drill string while operating are desired.